Improvement in locks



UNITED STATES PATENT OFFICE.

HENRY UNDERIOOD, OF TOLLAND, CONNECTICUT.

IMPROVEMENT IN LOCKS.

Specification forming part of Letters Patent No. 44,475, dated September 27, 1864.

.To all whom it may concern.-

Be it known that l, HENRY UNDEEwooD, ot' Tolland, in the county of Tolland and State of Connecticut, have invented a new and Improved Lock; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is an internal view ot' my invention, the case being in section, as indicated by the line a' x, Fig. 2; Fig. 2, a transverse section .of the same, taken in the line y y, Fig. 1.

Similar letters of reference indicate like parts.

The object ot' this invention is to obtain a lock of simple construction without the employment or use of a spring, thereby avoiding a part which is extremely liable to get deranged or out of working order, either on account of breakage due to an improper tempei ing, or'to oxidation, the latter contingency being sure to occur if the lock is at all exposed to moisture or dampness.

The invention consists in the employment or use of a cam applied to or used in connection with the bolt for operating the same, and also in using in connection with the cam one or more tumblers, all arranged substantially as Yhereinafter set forth.

A represents the case of the lock, which may be constructed in the usual or in any proper way; and B is the bolt which works.

through the side or end of the case, as usual.

C represents a. cam, a portion, a, of the edge ot'which is of circular form, and which is a portion of a circle of larger diameter than the other portion, b, which is of eccentric form and has a slot, C, made in it to receive a pin, d, on the bolt B. The portion b pnt' the cam is below the portion a, as shown in U is the key-hole through which the bit e of the key D is passed into the lock to turn the cam C, and by the turning ofthe cam, the bolt Bis shoved out or drawn into the case on account of the pin d fitting in the slot C,

which has an eccentric position with the axis of the cam. The cam is provided with a circular opening at its center, which works around an annular rim, ctx, in the case A. The heavier portion of the cam C being uppermost, it will be seen that it will have a tendency to drop or fall either to the right or left of its axis, according as its center of gravity passes to the right or left of its axis; hence a spring is compensated for, as the gravity of the cam performs that ofiice.

In order to render the lock difficult to pick, I employ a tumbler, D, which is arranged to slide up and down behind the cam U, and between guides d. This tumbler is simplya fiat plate, having a stud, e, projecting from it at right angles, and which passes through a curved concentric slot, f, in the cam, the upper and lower edges of said slot being notched, as shown at g in Fig. 1. The lower end of the tumbler l) is hollowed out in semicircular form and has abead or ward, h, upon it,which a groove, i, in the bit of the key receives, and which causes the tumbler to be raised when the key is turned. The tumbler has a tendency to fall and does fall by its own gravity when the key is withdrawn from the lock, and the stud e catches into one of th. notches in the lower edge of the slot f, there by preventing the turning of the cam and the drawing in of the bolt by illegitimate means. The key when turned raises the tumbler the proper distance so as to free the stud from the lower notches, g, but not so high as to cause the stud to engage with the upper notches, g-a contingency which would occur if a pick were inserted into the lock, as there would be no guide in moving the tumbler, as is the case when ,the key is used.

One or more tumblers may be used according to the kind or price of lock which may be required, or the tumbler may be dispensed with,lthus simplifying the construction, and the cam may beprolon ged or extended through and beyond the outer rim in a lever form to be moved by hand dispensing with a key, and thus forming a simple bolt.

Having thus described my invention, I claim as new and desire to secure by Letters Pat l1er D, one or more, provided with the stud e entand the Ward h, and the notched slot f in the l. The cam C, provided with the eccentric cam to receive the stud, all arranged substanslot C, und otherwise constructed as described, tiaily as and for the purpose specified.

iu connection with the pin d on the bolt B, all HENRY UNDERWOOD. arranged to operate substantially as and for Witnesses: the purpose set forth. y WILLIAM KEITH,

2. In combination with the eem C, the tuin- JOSEPH BISHOP. 

